// MIT License

// Copyright (c) 2019 Erin Catto

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#include "settings.h"
#include "test.h"

class EdgeShapesCallback : public b2RayCastCallback
{
public:
  EdgeShapesCallback()
  {
    m_fixture = NULL;
  }

  float ReportFixture(b2Fixture* fixture, const b2Vec2& point,
              const b2Vec2& normal, float fraction) override
  {
    m_fixture = fixture;
    m_point = point;
    m_normal = normal;

    return fraction;
  }

  b2Fixture* m_fixture;
  b2Vec2 m_point;
  b2Vec2 m_normal;
};

class EdgeShapes : public Test
{
public:

  enum
  {
    e_maxBodies = 256
  };

  EdgeShapes()
  {
    // Ground body
    {
      b2BodyDef bd;
      b2Body* ground = m_world->CreateBody(&bd);

      float x1 = -20.0f;
      float y1 = 2.0f * cosf(x1 / 10.0f * b2_pi);
      for (int32 i = 0; i < 80; ++i)
      {
        float x2 = x1 + 0.5f;
        float y2 = 2.0f * cosf(x2 / 10.0f * b2_pi);

        b2EdgeShape shape;
        shape.SetTwoSided(b2Vec2(x1, y1), b2Vec2(x2, y2));
        ground->CreateFixture(&shape, 0.0f);

        x1 = x2;
        y1 = y2;
      }
    }

    {
    b2Vec2 vertices[3];
    vertices[0].Set(-0.5f, 0.0f);
    vertices[1].Set(0.5f, 0.0f);
    vertices[2].Set(0.0f, 1.5f);
    m_polygons[0].Set(vertices, 3);
  }

    {
      b2Vec2 vertices[3];
      vertices[0].Set(-0.1f, 0.0f);
      vertices[1].Set(0.1f, 0.0f);
      vertices[2].Set(0.0f, 1.5f);
      m_polygons[1].Set(vertices, 3);
    }

    {
      float w = 1.0f;
      float b = w / (2.0f + b2Sqrt(2.0f));
      float s = b2Sqrt(2.0f) * b;

      b2Vec2 vertices[8];
      vertices[0].Set(0.5f * s, 0.0f);
      vertices[1].Set(0.5f * w, b);
      vertices[2].Set(0.5f * w, b + s);
      vertices[3].Set(0.5f * s, w);
      vertices[4].Set(-0.5f * s, w);
      vertices[5].Set(-0.5f * w, b + s);
      vertices[6].Set(-0.5f * w, b);
      vertices[7].Set(-0.5f * s, 0.0f);

      m_polygons[2].Set(vertices, 8);
    }

    {
      m_polygons[3].SetAsBox(0.5f, 0.5f);
    }

    {
      m_circle.m_radius = 0.5f;
    }

    m_bodyIndex = 0;
    memset(m_bodies, 0, sizeof(m_bodies));

    m_angle = 0.0f;
  }

  void Create(int32 index)
  {
    if (m_bodies[m_bodyIndex] != NULL)
    {
      m_world->DestroyBody(m_bodies[m_bodyIndex]);
      m_bodies[m_bodyIndex] = NULL;
    }

    b2BodyDef bd;

    float x = RandomFloat(-10.0f, 10.0f);
    float y = RandomFloat(10.0f, 20.0f);
    bd.position.Set(x, y);
    bd.angle = RandomFloat(-b2_pi, b2_pi);
    bd.type = b2_dynamicBody;

    if (index == 4)
    {
      bd.angularDamping = 0.02f;
    }

    m_bodies[m_bodyIndex] = m_world->CreateBody(&bd);

    if (index < 4)
    {
      b2FixtureDef fd;
      fd.shape = m_polygons + index;
      fd.friction = 0.3f;
      fd.density = 20.0f;
      m_bodies[m_bodyIndex]->CreateFixture(&fd);
    }
    else
    {
      b2FixtureDef fd;
      fd.shape = &m_circle;
      fd.friction = 0.3f;
      fd.density = 20.0f;
      m_bodies[m_bodyIndex]->CreateFixture(&fd);
    }

    m_bodyIndex = (m_bodyIndex + 1) % e_maxBodies;
  }

  void DestroyBody()
  {
    for (int32 i = 0; i < e_maxBodies; ++i)
    {
      if (m_bodies[i] != NULL)
      {
        m_world->DestroyBody(m_bodies[i]);
        m_bodies[i] = NULL;
        return;
      }
    }
  }

  void Keyboard(int key) override
  {
    switch (key)
    {
    case GLFW_KEY_1:
    case GLFW_KEY_2:
    case GLFW_KEY_3:
    case GLFW_KEY_4:
    case GLFW_KEY_5:
      Create(key - GLFW_KEY_1);
      break;

    case GLFW_KEY_D:
      DestroyBody();
      break;
    }
  }

  void Step(Settings& settings) override
  {
    bool advanceRay = settings.m_pause == 0 || settings.m_singleStep;

    Test::Step(settings);
    g_debugDraw.DrawString(5, m_textLine, "Press 1-5 to drop stuff");
    m_textLine += m_textIncrement;

    float L = 25.0f;
    b2Vec2 point1(0.0f, 10.0f);
    b2Vec2 d(L * cosf(m_angle), -L * b2Abs(sinf(m_angle)));
    b2Vec2 point2 = point1 + d;

    EdgeShapesCallback callback;

    m_world->RayCast(&callback, point1, point2);

    if (callback.m_fixture)
    {
      g_debugDraw.DrawPoint(callback.m_point, 5.0f, b2Color(0.4f, 0.9f, 0.4f));

      g_debugDraw.DrawSegment(point1, callback.m_point, b2Color(0.8f, 0.8f, 0.8f));

      b2Vec2 head = callback.m_point + 0.5f * callback.m_normal;
      g_debugDraw.DrawSegment(callback.m_point, head, b2Color(0.9f, 0.9f, 0.4f));
    }
    else
    {
      g_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
    }

    if (advanceRay)
    {
      m_angle += 0.25f * b2_pi / 180.0f;
    }
  }

  static Test* Create()
  {
    return new EdgeShapes;
  }

  int32 m_bodyIndex;
  b2Body* m_bodies[e_maxBodies];
  b2PolygonShape m_polygons[4];
  b2CircleShape m_circle;

  float m_angle;
};

static int testIndex = RegisterTest("Geometry", "Edge Shapes", EdgeShapes::Create);
